STOCKTON - A new lead on an old case led investigators to a home in Manteca, where authorities spent hours Thursday digging up what may be the remains of a woman who disappeared in 1990, police said.

Evidence recovered from a home in the 400 block of Park Avenue was turned over to the San Joaquin County Coroner's Office for analysis, said Officer Joseph Silva, a spokesman for the Stockton Police Department.

Investigators went to the home after receiving a tip about a 1990 missing-person's case, Silva said. Rene Smith, a neighbor who worked as a coroner's investigator for 15 years, said police removed what appeared to be a human torso, but Silva would not say whether authorities believe they unearthed human remains.

"They located a piece of evidence that they had to collect to determine exactly what it is, but we can't speculate until we know for sure," Silva said.

A search of The Record's archives turned up only one unsolved missing-person's case from 1990. Karen Michelle Sterzl was last seen Dec. 22, 1990, in Stockton at a Tuleburg Levee houseboat she shared with her boyfriend.

At the time, the 36-year-old woman's boyfriend said Sterzl told him she and her mother were going to Montana to visit her sister and planned to return New Year's Day. The man reported Sterzl missing Jan. 11, 1991.

Sterzl's mother told authorities she had not heard from her daughter in a month and had not planned a trip with her. Police said they found vehicles belonging to Sterzl in their usual parking spaces.

The case has remained unsolved for more than 22 years, but investigators may be on the verge of solving it.

"Our investigators follow up on tips that come in from the public daily," Silva said. "This tip was pretty credible, and because of that tip, we were able to collect potential evidence that might eventually solve this case."